What is X4 mode, and is there a noticeable difference between SATA mode and PCIE mode?

My last question is in relation to temperatures. I live in Townsville, Australia which is sub-tropical. At the moment we are coming out of winter, about 26 deg C or 79 deg F, not hot enough for aircon. My SSD is sitting at 60 deg C and the specs say a max of 70 deg C, should I be concerned?

x1 vs x4 is the number of lanes and equates to bandwidth. Depending on the drive you may find that it is limited by an x1 connection.

There are many differences between SATA and PCIE. First, your drive is one or the other so it's not just a random setting. They share the M.2 connection standard but work very differently. SATA is just like a 2.5" SATA SSD and it connects to the SATA controller. NVMe (PCIe) drives are PCI devices like a graphics card and they either connect to the chipset or directly to the CPU depending on several factors. Generally speaking NVMe drives can be significantly faster because they are not limited by the SATA controller.

x1 vs x4 is the number of lanes and equates to bandwidth. Depending on the drive you may find that it is limited by an x1 connection.

There are many differences between SATA and PCIE. First, your drive is one or the other so it's not just a random setting. They share the M.2 connection standard but work very differently. SATA is just like a 2.5" SATA SSD and it connects to the SATA controller. NVMe (PCIe) drives are PCI devices like a graphics card and they either connect to the chipset or directly to the CPU depending on several factors. Generally speaking NVMe drives can be significantly faster because they are not limited by the SATA controller.

That explains a lot mate. I had my new NVME is M2_1 which was set to SATA. Thanks.